Process of separating solid salts of ammonium and of the alkalies or alkaline earths



Oct. 29, 1929. P. osswALD ET AL 1,733,272

PROCESS 0F SEPARATING SOLID SALTS OF AMMONIUM AND OF THE ALKALIES OR ALKALINF EARTHS Filed Oct. 19. 1925 "www"" -"mmC@ l l I l I gwtwnow: @uu/111A,

l T u l r l l||.l lll Lf h Patented 29, i929` NT OFFICE SALD, E EFHEIM-ON-THE-TAUNUS, MD KQNRAD SCHAD, 0F BIGGEST- @N-TEE-AT, GERMANY, ASSIG-NOEJS T0 I. G, FARBENNDUSTRIE AKTIENGESELL- @F FEUNEFRT-'ON-TEE-MMN,

llppication filled @ctoher 19, m2o, Serial Eo. @3,55% and in Germany october 3i,

'lhe object of our invention is a new process for producing solid salts oi ammonium and. oi the alkali metals or alkaline earth metals from mixtures thereoie obtained by interaction the characteristic *feature o' the invention consisting in subjecting said mixtures to an elutriating process.

l-litnerto. 'the general practice has been, to

- separate by fractional.crystallization the lof) readily soluble salts ci ammonium obtained by interaction from the salts of the alkali metals or alkali earth metals. By changing the temperature and adding solid or liquid precipitating agents the solubility of the salts could be induenced. 'lhe use oi such methods is rather expensive, because it oo nsumes a great deal ofenergy and material whilst the amount ot the direct yield is very` smalland because it is necessary in most cases to increase these yields by working up a smaller or larger quantity oi intermediate productsb The invention is based on the fact that almost 'all oit the ammonium salts in contrast to the salts of the alkali metals or the alkaline earth metals possess a considerably lower specic weight and at the same time crystallise in a diffuse, for instance, like form, whereby their ascent in the liquids used vfor the elutriating operation is promoted.

lalereaiter we give a description of a manner in which our invention may be put into practice, taking, or example, the separation ci sodium lnitrate and ammonium chloride prepared from common salt and ammonium The separation of such a mixture whichis easily obtainable from common salt and ammonium nitrate, is of particular technical importance 'for the reason that, hither- I the preparation ot articial sodium nied the use of the costly sodium carbonate and, therefore, entailed great exn lin our new process we use, instead ot salt,. Alowing examples will illustrate in a featherr onate, cheap common salt (rock f our invention and how it may' be a vessel itprovided with a stirrer-2 cubic meters of the liquor used for the reaction which is agitated in a circle and comprising the following: 1000 'kgm or" water, 773 kgmo oi sodium nitrate, 272 kgm. of ammonium chloride, 912 kgm. of ammonium nitrate of a specic gravity of about 1,4. Into this liquor, which is kept at a temperature oit about C., are introduced within 2 hours 380 kgm. of finely powdered rock salt. After having added three quarters of the above stated quantity of common salt there are turther added within one hour 520 kgm. of solid ammonium nitrate. The reaction being now complete, there are obtained about 900 kgm.

oi a salt mixture, suspended in mother liquor,

comprising coarse-grained sodium nitrate, the grains being of a size of 9,5 to l mm. and of a density, oir' about 2,3 and a tine-grained ammonium chloride the grains being of a size of about 0,02 mm. and of a density of about 1,5. This mixture is dischar ed into the elutriating apparatus B whic is oi the known type and which is advantageously fed with a reaction-liquor of a specific gravity of 1,4. ln this apparatus the separation of the sodium nitrate takes place. The elutriating process may be facilitated by an undercurrent of liquor flowing in from 'u and passing upward between wed e shaped grids .1o. The lighter ammonium c loride flows over into the settling tank C where it is isolated from the liquor; the latter being returned into the cycle oi' the process.

(2) into a reaction liquor, composed of 1000 litres of water, 810 kgm. of sodium nitrate, 295 kgm. of ammonium chloride and- 1445 kgm. oi ammonium nitrate are introduced at 65 C. 250 kgm. of unground rock salt and BaO lrgm. oir' ammonium nitrate. After about 1/2 hour, the dissolution, and, consequently, the conversion, is complete. By allowing the clear solution to cool, G t300 lrgm. oi a crystalline mixture will be separated, consisting of coarse-grained sodium nitratef-size o grains above l mm.- nd of ammonium chloride in a form resembling that oi line Jleathers; these two components can be easily isolated tromeach other by elutriation possess a degree oi purity of teraction of potassium chloride and ammonium nitrate. In this -way a concentrated nitrogenous potassium manure can be obtained which will be particularly welcome to the farmer, in view of the fact that by using it he can save a good deal of expense connected with the transport, the storage and the strewing of this manure.

Our new process is also a plicable to the interaction of ammonium sul ate and sodium chloride, whereby sodium sulfate and ammonium chloride are obtained.

'If the salts, obtained by the above described process, are not yet suiiciently purewhich may be the case 1f they are to be used for some special purposes-the salts may be subjected to a further purifying process. We have found that the mother liquor saturated with the two salts produced as abovedescribed, when heated to a higher temperature, is capable of dissolving the impurities contained in the crude salts and consequently may be used for the said purpose. The fact that there is dissolved at the same time a small quantity of the salt to be purilied, is of little importance. Thus, the crude salts obtained by the elutriating process are puried by washing them with the warmed mother liquor. This method oli'ers the great advantage that thereby any further re-crystalizing-or evaporating operations are avoided. For instance, there my be heated from 25 to 40 C. 100 kgm. of sodium nitrate (about 90 per cent strength), obtained bythe interaction of sodium chloride and ammonium nitrate, with 100 litres of the reaction liquor. After about ,1/2 hour the adhering'ammonium chloride together with some sodium nitrate is dissolved. There remain after the solution has been ltered by suction about kgm. of sodium nitrate having a degree of purity of sri-98%.

' We claim:

1. The process which consists in the steps of producmg a mixtureof a solid salt of ammonium and a solid salt of a metal of the alkali and alkaline earth metal seriesv by double decomposition in solution in a liquid medium and then separating the two components of the mixture by means of an` elutriating process at ordinary temperature.

2. The process which consists in the steps of producing a mixture of crystals of ammonium chloride and of otassium nitrate by double decomposition Orp ammonium nitrate and potassium chloride in solution in a liquid medium and then separating the twocomponents of the mixture by means of an elutriating process at ordinary temperature.

tures.

In testimony whereof, we aix our signa- DR. PHILIPP osSwALD. DR.. KONRAD soHAD. 

